The LM51501-Q1 device is a wide input range automotive boost controller designed for automotive start-stop or emergency-call applications. The device can maintain the output voltage from a vehicle battery during automotive cranking or from a backup battery during the loss of vehicle battery. The wide input range of the device covers automotive load dump transient. The control method is based upon peak current mode control.

To extend the battery life time, the LM51501-Q1 features a low I_Q standby mode with automatic wake-up and standby control. The device stays in low I_Q standby mode when the boost operation is not required, and automatically enters the wake-up mode when the output voltage drops below the preset wake-up threshold. High value feedback resistors are included inside the device to minimize leakage current in low I_Q standby mode.

The LM51501-Q1 operates in one of two selectable configurations when waking up. In Start-Stop configuration (SS configuration), the device runs at a fixed switching frequency without any pulse skipping until entering into the standby mode, which helps to have a fixed EMI spectrum. In Emergency-Call configuration (EC configuration), the device will skip pulses as it automatically alternates between low I_Q standby mode and wake-up mode to extend the battery life in light load conditions.

The LM51501-Q1 switching frequency is programmable from 220 kHz to 2.3 MHz. Fast switching (≥ 2.2 MHz) minimizes AM band interference and allows for a small solution size and fast transient response. A single resistor at the VSET pin programs the target output regulation voltage as well as the configuration. This eliminates the need for an external feedback resistor divider which enables low I_Q operation. The device also features clock synchronization in the SS configuration, low quiescent current in shutdown mode, a boost status indicator, adjustable cycle-by-cycle current will limit, and thermal shutdown protection.